Which of the statements about LISP is correct?

Question

Options

• APxTR is required to enable remote LISP sites to communicate with the hub LISP site.
• BPxTR is required to enable remote non-LISP sites to communicate with the hub LISP site.
• CLISP requires DMVPN to be enabled.
• DLISP requires NAT46 at the Internet edge when connecting to non-LISP sites.

• A
  6% (2)
• B
  82% (28)
• C
  3% (1)
• D
  9% (3)

Explanation

B is correct: LISP (Locator/ID Separation Protocol) uses ITRs (Ingress Tunnel Routers) and ETRs (Egress Tunnel Routers) to encapsulate and decapsulate traffic between LISP-capable sites. However, non-LISP sites cannot participate in LISP encapsulation natively. A PxTR (Proxy xTR) acts on behalf of non-LISP sites - it serves as both a Proxy-ITR (receives non-LISP traffic destined for LISP sites and encapsulates it) and a Proxy-ETR (decapsulates LISP traffic and forwards it to non-LISP destinations). Without a PxTR, non-LISP sites cannot communicate with LISP sites. A is false because remote LISP sites communicate with the hub LISP site using standard LISP encapsulation (ITR/ETR) without needing a PxTR - PxTR is specifically for non-LISP interoperability. C is false because LISP is a completely independent overlay architecture that does not depend on or require DMVPN. D is false because LISP does not use NAT46 for non-LISP connectivity - PxTR serves that interoperability role.

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